Many devices have been constructed to indicate the attempted tampering of containers. Generally, an outer cap member is disposed over an inner fitment. The outer cap member provides a seal which when ruptured indicates tampering. The inner fitment provides a cover to the container which in most cases is removable and resealable. The outer cap may be ruptured by various means. In most instances, the cover is ruptured during the unscrewing process.
For example, U.S. Pat. No. 2,124,874 to Conner et al, issued July 26, 1938, discloses a container closure including an inner fitment and an indicator member. The fitment is covered or at least partly covered by the indicator member or outer closure.
The U.S. Pat. No. 2,162,752 to Schauer, issued June 20, 1939, discloses a tamper proof closure wherein the closure snaps over a rim of the inner fitment.
The U.S. Pat. No. 4,433,790 to Gibson, issued Feb. 28, 1984, discloses a tamper proof closure wherein the outer indicator cap is snapped onto the inner fitment prior to assembly.
None of the aforementioned patents disclose a one way screw on outer indicator cap which is not removable by reverse screwing and has a central weakened portion so that tightening of the cap over a second series of threads splits the cap.